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Transistor was first invented in 1948 by J. Bardeen and W.H. Brattain of Bell Telephone Laboratories U.S.A. Though transistor is only slightly more than 40 years old, yet it is fast replacing old electronic equipment (vaccum tubes like triode and pentode) in almost all applications because of its innumerable merits viz longer life, higher efficiency, more mechanical strength, light in weight, smaller in size, smaller power consumption etc. It is also known as Bipolar Junction Transistor (BJT) since its operation depends upon the interaction of both the majority and minority carriers. This device has now become more or less heart of most of the electronic applications.  TRANSISTOR  A semiconductor device consisting of two pn junctions formed by sandwitching either p-type or n-type semiconductor between a pair of opposite types is known as a transistor. Accordingly, there are two types of transistors, namely:  (ⅰ) npn transistor (ⅱ) pnp transistor (ⅰ) npn Transistor : A tr...

 INDUCTORS The electronic component (mostly a coil) which opposes the change of current in circuit is named an inductor. the power of the coil or inductor thanks to which it opposes the change of current flowing through it's referred to as its inductance. The inductance of an inductor can also be defined because the ability of an inductor (coil) to supply induced voltage when the present varies through it. The unit of inductance is henry which is known as after Henry . The schematic symbol of fixed and variable inductor. An inductor may be a component which offers high impedance to a.c. but very low impedance (opposition) to d.c. the standard function of an inductor, within the electronic circuit, is to dam a.c. signal but to pass d.c. signal (or voltage). The variable inductors are utilized in tuning circuits (for changing the resonant frequency) for radio frequencies. These also are used for impedance matching. TYPES OF INDUCTORS The inductors, like resistors and capacitors, can...

 CAPACITORS The two conducting plates separated by an insulant (called dielectric) forms a capacitor. The essential purpose of a capacitor is to store the charge. The capacity of a capacitor to store charge per unit electric potential is named its capacitance. The unit of capacitance is farads (F). However, the unit farad being overlarge , the capacitors are specified. practically in microfarads (µF) or picofarads (pF). A capacitor may be a component which offers low impedance to a.c. but very high impedance (resistance) to d.c. In most of the electronic circuits, a capacitor has d.c. voltage applied, combined with a way smaller ac. signal voltage. the standard function of the capacitor is to dam the d.c. voltage but pass the a.c. signal voltage, by means of charging and discharging. These applications include coupling, bypassing and filtering for a.c. signal. The schematic symbol of fixed and variable capacitor (C) is shown in figure. Types of Capacitors All the capacitors have t...

RESISTORS What is Resistor? Resistor is a component, used to limit the amount of current or divide the voltage in an electronic circuit. The ability of a resistor to oppose the current is called resistance. The unit of resistance R is ohm for which the symbol is 𝛀 (omega). Types of Resistors Each resistor has two main characteristics i.e. its resistance (R) in ohms and its power rating in watts (W). The resistors having wide range of resistance (from a fraction of an ohm to many mega ohms) are available.  The power rating may be as lower 1/10 W to as high as several hundred watts. The value of R is selected to obtain a desired current I or voltage drop IR in the circuit. At the same time wattage of the resistor is selected so that it can dissipate the heat losses without overheating itself. Too much heat may burn the resistor. From the operating conditions point of view, the resistors may be classified as fixed resistors and variable resistors. 1. Fixed Resistors The resistors w...

Electronic Circuits are designed to obtain a particular function. For this, a number of electronic components are suitably connected. Although we shall study the function of various components in detail, however, we shall study in general about these components. Electronic Components All the electronic circuits (simple to complex) contain a few basic components such as resistors, capacitors, inductors, tube devices and semiconductor devices. The first three components resistors, capacitors and inductors are called the passive components, whereas, the remaining two components tube devices (such as vaccum diode, vaccum triode, vaccum pentode, gas diode, thyratron etc.) and semiconductor devices (such as junction diode, zener diode, transistor, field-effect transistor, unijunction transistor, silicon control rectifier, tunnel diode etc.) are called the active components. Passive Components The electronic components which are not capable of amplifying or processing an electrical signal are...